The present invention relates to secondary conduit for transmission carriers and, in particular, to a secondary conduit integrated into a cured in place pipe for carrying electronic or fiber optic transmission cables.
It is generally well known that with the advent of broadband communications it has been difficult to locate transmission facilities at existing facility locations. The location of transmission facilities such as metallic and fiber optic cables has required creative solutions. Cable has been hung from existing transmission poles and fiber optic cable has been placed in protective conduit hung from poles as well as in trenches placed along existing highways and rail facilities. In open fields these methods tend to work well and at relatively acceptable costs. However, in cities where the existing infrastructure does not permit trenching of cables or additions to over head wiring, other solutions have been devised.
One such method is the proposed use of sewer lines in which cables can be run through out sewer system. One of the attractive features of such method is that sewers are generally connected to all of the existing building, thus providing ready access to a transmitter""s potential customer base. It also obviates the need to destroy streets in order to place trenches and cables in the ground. The methods proposing the use of such systems, insert the conduits inside the sewer or storm pipe with the help of robots, and use anchors, bolts or other fasteners to hold the conduits which carry the optical fiber cable in their required positions. Typically, circular sleeves or rings made of steel, which open inside the pipe, holds itself and the conduits in position.
Notwithstanding the seeming benefits of using these existing sewer line systems, significant problems exist. One of the most significant is that most existing sewer lines are old and in disrepair. The means currently proposed for use and used to place the transmission carriers conduits in the sewer systems accelerate their deterioration and the capital value of the in-sewer placed conduits.
The present invention provides an alternative to the current proposed in-sewer methods by utilizing, in one embodiment, a system well known in the sewer relining art of cured in place pipe (xe2x80x9cCIPPxe2x80x9d). CIPP is used for the relining of existing sewers. Thus, it is an object of the present invention to provide a novel secondary conduit within the CIPP used for relining deteriorating or old sewer systems. The secondary conduit within the CIPP provides a simple way of placing transmission cables within the infrastructure of cities and enhance the sewer systems. It is thus a further object of the invention to provide a system in which the capital investment of utilizing sewer systems for transmission cables is enhanced. It is another object of the invention to provide for cities facing sewer relining an opportunity to find third party funding sources to help finance such reconstruction or relining by rental of the secondary conduits or providing the CIPP.
Generally, the present invention provides at least one secondary conduit for a transmission carrier such electrical or optical cable used to transmit signals such as broadband internet signals. The secondary conduits for such carriers are preferably provided as an integral portion of a first conduit that comprises at least one arcuate sidewall which defines the elongated first conduit. The first conduit is typically used for the conveyance of fluids such as water, sewage, or storm water. A second conduit is integrally formed within said one first arcuate sidewalls to form a secondary conduit that is coextensive with the length of the first conduit and is adapted to receive one or more transmission carriers.
In a preferred embodiment of the invention, both the first and second conduits are of a substantially circular cross-section, but can be of other shapes including elliptical, oval or the like. The secondary conduit can be of a different cross-sectional profile from the first conduit and in other preferred embodiments more than the secondary conduits are used, each of which may have a different cross-sectional profile. Most preferably the first conduit is substantially circular in cross-section profile while the secondary conduit has either a substantially circular or oval profile. The secondary conduit typically has a cross-sectional diameter sufficient to provide access to carriers such as optical fiber. In the preferred embodiments of the invention, the inner surfaces of the secondary conduit are of a coefficient of friction sufficiently low to easily pull fiber optics through extended lengths without the necessity of including protective conduit for such cable.
While the invention may be made of pre-formed sections of concrete extrusions or castings, extruded polyethylene or propylene or other material which can be used for conveyance of fluids, the invention has particular advantages in association with cured in place pipe (xe2x80x9cCIPPxe2x80x9d). CIPP has been used in the construction industry for many years and, in particular, has been used to reline deteriorating sewer and storm sewer systems owned by public authorities and the like. Thus by using CIPP as a preferred embodiment of the present invention, a significant enhancement to the infrastructure of sewer system can be undertake while providing means for providing transmission carriers to buildings without damage to other portions of the municipal infrastructure, such as streets, sidewalks or other parts of the public access.
In one aspect of the invention, a secondary conduit positioned and anchored between the felt layers used to reinforce the first conduit that will be cured in place within and existing sewer or like system. This secondary conduit carrier can be placed or positioned between the layers during or after the manufacturing of the liner. In preferred embodiments, the secondary conduit comprises a rigid or semi-rigid polyethylene liner which may be used to form the secondary conduit and removed after formation or left in place. In another preferred embodiment, the secondary conduit is formed on outside of the CIPP conduit adjacent to the server conduit. Other advantages of the present invention will become apparent from a perusal of the following detailed description of a presently preferred embodiments of the invention-taken in connection with the accompanying drawings.